The fundamental question of how cells of bones and teeth assemble and mineralize their respective matrices in such a coordinated and superbly biofunctional way is still largely unanswered. The Protein Chemistry Unit has been performing a variety of experiments and collaborations to help determine the structure-function relationship of several of the more interesting noncollagenous proteins. Publications fall into four general categories. 1) The SIBLING family of integrin-binding matrix skeletal matrix proteins that include bone sialoprotein, osteopontin, dentin matrix protein 1 and dentin sialophosphoprotein. We have discovered that at least the first three of these protein can bridge complement Factor H to integrins or CD44 (for OPN and DMP1) and inhibit the lytic pathway of complement. 2) Advances in the understanding of McCune-Albright Syndrome (MAS) and Fibrous Dysplasia of bone including data indicating that the disease directly affects the osteogenic lineage. We have continued to develop a new assay that aids in the rapid detection of the mutation. 3) Bone sialoprotein (BSP) has been shown to mediate human endothelial cell attachment and migration as well as promoting angiogenesis 4) Finally we have continued our exploration of the possible role of bone sialoprotein in osteotropic cancers. With our colleagues, we have extended our observations to include expression of BSP in the sera of patients with a number different cancers.